The invention relates to a cam-independent drive for folding components, such as folding blades or movable folding jaws, on folders disposed downline from rotary printing machines.
The published patent document WO 98/06581 discloses a cylinder drive for cylinders of rotary printing machines. The drive motor of the cylinder is flange-mounted on an eccentric bushing accommodating the cylinder bearing and, when the eccentric bushing is suitably adjusted by an actuating cylinder, is also moved synchronously with the cylinder. The drive motor and the cylinder journal are connected to one another via an interposed coupling.
In the published German Patent Documents DE 195 30 956 A1 and DE 196 16 629 A1, devices for changing over a product-guiding cylinder in a folder are described. These German patent documents disclose a device for changing over a product-guiding cylinder of a folder from collecting to non-collecting production and the reverse. The collecting cylinder is equipped, on the circumference thereof, with at east one folding blade and at least one set of holding elements. Also provided are both a folding-blade control cam, having a circumferential contour forming a control cam for actuating elements which generate the movement of the folding blades, and a holding-element control cam having a circumferential contour forming a control cam for the actuating elements which generate the movement of the holding elements. A device for the drive-independent movement of one of the control cams in order to change over or convert between collecting and non-collecting production is also provided, as well as automatically activated actuating elements for the radial movement of the actuating elements of the folding blades and of the holding elements, which move the actuating elements both axially and radially. The mechanical outlay or expense shown in the two last-mentioned publications for driving the folding elements is very high, and the ability to displace the control cams actuating the latter is very great.
In folders disposed downline from rotary printing machines, the cylinders carrying folded products are provided with folding components, such as folding blades, folding jaws, pins or holding devices for gripping the copies. These folding components are generally driven by control rollers which run on cam sections defining the actuating time of the control roller of the corresponding folding component. The surfaces of the control cam are produced in special production steps, are ground and machined with an extremely high surface quality. In order to increase the service life, the surfaces on which the control cams run are subjected to single-stage or multi-stage hardening processes. The control cams for the folding components therefore constitute components, in a folder, which are very complicated to produce and are, therefore, extremely costly.
In conventional cam/control roller arrangements for driving folding components in a folder at high speeds, lifting the control roller off the running surfaces of the cams occurs, caused by the action of centrifugal force. Consequently, the control rollers have high bias forces applied to them in order to suppress any lifting of the rollers off the running surfaces of the cams. Undesired associated phenomena of the bias forces applied to the control rollers are the high forces to which the components are therefore forcibly subjected, which can lead to insidiously occurring premature material fatigue.
In view of the indicated technical problem, it is an object of the invention to provide a cam-independent drive for folding components that serves as a cost-effective replacement for cam control, and achieves a low maintenance requirement.
With the foregoing and other objects in view, there is provided, in accordance with one aspect of the invention, in a folder, a folding cylinder having folding components accommodated on the periphery thereof and being phase-dependently operatable, and cylinder segments for carrying the folding components, the cylinder segments being adjustable in relation to one another and being mounted coaxially in side walls, comprising separate drives, respectively, for driving each of the folding components, a rotary leadthrough via which energy is supplied to the separate drives, and a speed controller for speed-dependently controlling the separate drives.
In accordance with another feature of the invention, a respective speed controller is assigned to each of the separate drives.
In accordance with a further aspect of the invention, in the folder, the speed controller is common to all of the separate drives and is disposed outside the folding cylinder.
In accordance an added feature of the invention, the folding cylinder includes a rotary encoder for transmitting the position of the respective folding components to the speed controller.
In accordance with an additional feature of the invention, the rotary encoder has a resolving power of 213 scale divisions.
In accordance with yet another feature of the invention, the folding cylinder includes a transmitter/receiver pair via which a reference position is transmittable between a stationary component and a rotating component.
In accordance with yet a further feature of the invention, the folder includes a cutting cylinder, and a reference position of the folder is determinable by sensing the rotary position of the cutting cylinder.
In accordance with an added aspect of the invention, there is provided an assembly of the folder and a rotary printing machine disposed upline therefrom, wherein the rotary printing machine includes a transfer roller, and wherein a reference position of the rotary printing machine is determinable by sensing the rotary position of the transfer cylinder.
In accordance with another feature of the invention, the folding cylinder includes an optical wave guide via which the reference position is transmittable to the speed controller.
In accordance with a further feature of the invention, the folding cylinder includes mechanical transmission elements provided between the drive and the respective folding components.
In accordance with an added feature of the invention, the folding components are mounted on shafts formed at least partly of titanium.
In accordance with yet another aspect of the invention, there is provided a method for operating, independently of control cams, folding components accommodated on the circumference of a folding cylinder, which comprises: determining a reference position of at least one of a folder and a rotary printing machine; positioning the folding components with respect to the determined reference position; and transmitting to a speed controller an offset between the reference position and actual positions of the folding components.
In accordance with still another mode, the method of the invention includes determining the reference position by determining the rotary position of a cutting cylinder in the folder.
In accordance with still a further mode, the method includes determining the reference position by determining the rotary position of a transfer cylinder in the rotary printing machine.
In accordance with another aspect of the invention, there is provided a folder for a rotary printing machine, having a folding cylinder equipped, on the periphery thereof, with phase-dependently operatable folding components, the folding components being movable relative to one another in accordance with a format and a folding mode and being accommodated coaxially in side walls, comprising a separate drive for driving the folding components, a rotary leadthrough via which energy is supplied to said separate drive, and a speed controller via which the separate drive is speed-dependently drivable.
In accordance with a concomitant aspect of the invention, there is provided a rotary printing machine in combination with a folder which is equipped with at least one folding cylinder having, on the periphery thereof, phase-dependently actuatable folding components which are format-dependently and folding mode-dependently movable relative to one another and are accommodated coaxially in side walls, comprising a separate drive for driving the folding components, a rotary leadthrough via which energy is supplied to the separate drive, and a speed controller for speed-dependently driving the separate drive.
The advantages associated with the method modes and the features according to the invention are many and various. The control cams, which are provided at the ends of the cylinders carrying the folded copies, for the control rollers operating the folding components can be dispensed with, as can also the complicated assembly work, such as torque presetting and so forth associated with this type of control when assembling the cylinders. Consequently, more cost-effective assembly and maintenance of the folding cylinders can be achieved; components which are complicated and expensive to produce, such as control cams with surfaces which have to be machined very accurately, and the biasing devices necessary at high production speeds for the control rollers running on the cam running surface, can be dispensed with.
In a further development of the basic idea of the invention, each of the drives for the folding components can have a separate speed controller assigned thereto and, equally well, a speed controller that is common to all the separate drives can be provided outside the folding cylinder. In the context of this application, the generic term folding cylinder is meant to include a folding-blade cylinder, a folding-jaw cylinder, a separate pin cylinder, a collecting cylinder and a gripper cylinder as well as a transport cylinder.
In order to feed back and detect the actual position of the folding components, the latter can advantageously have rotary encoders assigned thereto, which can have a very high resolving power, for example up to 213 scale divisions. The rotary encoders can be assigned directly to the folding components, in order to detect their present and actual position.
The reference position of the folder or of the rotary printing machine preceding or disposed upline from the latter is preferably determined and transmitted between a stationary component and a rotating component, via a transmitter/receiver pair. An example of such a rotating component may be, for the folder, the cutting cylinder separating the copies from the material web and, for the rotary printing machine, the transfer cylinder of one of the printing units.
If the speed controllers for the drives of the folding components are accommodated, for example, on the shafts of the folding components themselves, the reference position can be transmitted to the speed controller via optical waveguides over fiber optic or similar devices. By the transmitter/receiver parts, the reference position may thus be transmitted to a large number of speed controllers assigned individually to folding components. The folding components, such as folding blades, the moving part of the folding jaws, pins and grippers on the cylinder, can either be moved in an oscillatory manner directly by drives accommodated on the actuating shafts or, on the other hand, transmission elements such as belts, gearwheels or the like can be provided between the shafts accommodating the folding components and the drives. In order to achieve the lowest possible moment of inertia and, at the same time, ensure adequate mechanical strength, the shafts accommodating the folding components can be produced from titanium or titanium alloys.
By the method according to the invention, in order to achieve the cam-independent operation of the folding components accommodated on the circumference of a folding cylinder, initially, the reference position of the folder and/or of the rotary printing machine preceding or located upline of the latter is determined. Then, the then current, actual positions of the folding components are determined, and the offsets between the reference position and the then current position is transmitted to the drives. The reference position used for determining the reference position of the folder or the rotary printing machine can, on the one hand, be the position of the cutting cylinder of the folder or, on the other hand, the position of the transfer cylinder of a printing unit of the rotary printing machine.
Folding cylinders according to the invention and the method proposed by the invention for operating folding components can advantageously be employed on folders with and without a collecting mode, it being possible for the thickness of the copies to be kept variable throughout, depending upon the production requirement in the printing plant or print shop.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a cam-independent drive for folding components, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.